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W T Barham H J Schoonbee J G Visser 《The Onderstepoort journal of veterinary research》1989,56(1):67-71
The narcotizing potential of various rectified current configurations on Oreochromis mossambicus was investigated. A 50 Hz, 200 Vp. half-wave rectified current, applied for 30 s, was found to be a suitable configuration for electronarcosis. 相似文献
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东阿黑驴是以德州驴为基础群向皮肉兼用型方向选育的新品种,本研究拟在其现有育种方案的基础上,探讨不同育种措施的最优化组合方案,为建立优质、高效的东阿黑驴育种体系奠定基础,为中国驴育种实践提供参考。本研究根据东阿黑驴的生产和育种现状,以选择指数法和基因流动法为基本方法,应用育种规划程序ZPLAN分析东阿黑驴现行育种方案的育种成效,对影响育种成效的各个因素进行优化分析,最终确定优化后的育种方案。结果表明,现行方案在投资规划期内可完成的遗传进展和育种效益分别为271.78和1 123.70元/（头·年）,世代间隔为5.24年,每年每个性状遗传进展分别为断奶重提高1.50 kg,18月龄体重提高0.09 kg,初产年龄缩短0.02 d,产犊间隔缩短0.17 d,皮产量增加1.04 kg。对影响育种的因素进行不同水平的组合分析,当群体规模理想状态为30 000头,主动育种群比例为0.5,育种群中种子公驴、测验公驴和种用母驴使用年限为1年,种子母驴使用年限为2年,生产群中公、母驴使用年限为1年时,可获得最大的育种遗传进展和育种效益,分别为320.40和2 945.00元/（头·年）,比现行育种方案分别高出17.9%和162.0%。东阿黑驴目前的育种方案没有达到理想育种状态,有较大的改进空间。研究通过对育种主要影响因素的不同水平优化组合,得到了最优的育种方案,使遗传进展和育种效益达到了最大化。 相似文献
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The aim of this study was to study the organizational culture of ten Dutch veterinary practices. In each practice, two veterinary nurses, two associates and two partners filled out the Organizational Culture Assessment Instrument for the current and preferred situation. Results showed that practice culture could be characterised best as the clan culture and, to a lesser extent, an adhocracy culture. The market culture was least prevalent. The family, adhocracy and hierarchy cultures were preferred above the market culture. The difference between current and preferred (i.e. the discrepancy) cultures was highest for the veterinary nurses, followed by the associates and smallest for the partners. Agreement between the three groups was stronger for the preferred situation than for the current situation. 相似文献
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1. The effect of stunning current on the time to recovery of physical activity, and on somatosensory evoked potentials (SEPs) in the brain, was examined in broiler chickens. 2. Increasing stunning current was associated with an increase in the time to recovery of tension in the neck muscles and with an increase in the incidence of loss of SEPs. 3. Currents greater than 105 mA per bird provided 52 s or more of apparent insensibility; currents greater than 120 mA were associated with absence of SEPs following the stun. 相似文献
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W T Barham H J Schoonbee J G Visser 《The Onderstepoort journal of veterinary research》1988,55(4):205-215
The effects of wave form, voltage, frequency and current as well as application time on the narcotizing ability of alternating current were investigated. A 60 Vrms, 50 Hz sine wave current applied for 30 s produced narcosis of sufficient duration to enable handling and blood sampling. A triangle wave form was inferior in narcotizing ability to both sine wave and square wave forms. Duration of narcosis increased with increasing water conductivity but was reduced by increasing water temperatures. 相似文献
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Chickens were electrically stunned either when their bodies and feathers were wet or when they were dry. The time to recovery of muscular activity following stunning with 81 mA was assessed, and it was found that it was quicker in the wet birds. When hens which had previously been implanted with electroencephalogram electrodes were stunned with 119 mA it was found that the prevalence of somatosensory evoked responses during the first 60 seconds after applying the current was not significantly influenced by the wetness of the birds. It was concluded that electrical stunning with low currents in wet birds leads to a lower prevalence of ventricular fibrillation at stunning and a shorter lasting stun in the non-fibrillated birds. This effect is possibly due to some of the current tracking over the bird's wet body rather than through the brain. 相似文献
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Ten ducks were subjected to electrical stunning with their heads completely immersed in the water of a waterbath, and 10 ducks received the same current while only the bill and skin over the crop made contact with the water. The effect on visual evoked responses in the brain was examined. A higher proportion of birds had lost their visual evoked responses immediately following the current with whole head immersion. It is suggested that crop and bill immersion is less effective in disturbing brain function than whole head immersion. 相似文献
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Somatosensory evoked responses in the chicken's brain were examined before and after stunning with a 350 Hz pulsed DC. When the current was greater than 120 mA, 93 per cent of the birds lost their evoked responses for at least 60 seconds. On this basis 120 mA per bird is recommended as an acceptable current for commercial use. 相似文献
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Gene contributions of foreign populations as well as coefficients of inbreeding and relationship were calculated in 1918 South German Coldblood horses registered in Bavaria in 2003. Based on nearly complete 8-generation-pedigrees (index of pedigree completeness: 76%) the mean coefficient of inbreeding was 23%. After considering missing pedigree data, the mean coefficient of inbreeding was 3%. The rates of inbreeding per generation in the current population amount to about 0.43% over the last eight generations and to about 0.15% in the forthcoming generation. In the total current population, the mean degree of relationship was 6%. The proportion of purebred South German Coldblood horses in the current population is about 43%. As the Noric horse is of same origin as the South German Coldblood, these two breeds can be considered as an entity and thus the proportion of purebred genes in the current Bavarian South German Coldblood population reaches more than 93%. The Suffolk Punch and Thoroughbred Horse were the most important contributors to the current South German Coldblood population, whereas the Rhenish-German and Black Forest Draught Horse as well as the Percheron had neglectable influences. The effective population size in the current Bavarian South German Coldblood population is Ne = 332. 相似文献
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我国南方草地资源开发利用模式的探讨 总被引：9，自引：3，他引：6
我国南方草地资源十分丰富，但利用率却很低。通过综合分析南方草地资源现状、优势和问题，提出了南方草地利用的持续发展战略，发展方向和主要生产经营模式以及南方草地生产效率的评价体系。 相似文献
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通过对青海省乐都县容生生态养殖场现状和原有规划的调查与分析,结合现有生产环境和资源条件,对其场区布局进行重新规划,并对其生产工艺和场房利用进行了设计和改进。结果显示,该猪场可以在科学设计、合理规划的基础上完成其原定目标,并在调整其发展重点后实现万头养殖规模。 相似文献
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D B Brunson M A Collier E A Scott L J Majors 《American journal of veterinary research》1987,48(7):1082-1086
A monopolar electrode was implanted surgically in the canine tooth dentine layer to evaluate pain threshold responses of horses. A constant-current stimulator was used to deliver a known electrical current to the tooth pulp nerve. A single stimulus of 2-ms duration, repeated at greater than or equal to 20-s intervals, was used to elicit a head lift response. The lowest current level that produced 3 positive head lift responses was recorded as the pain threshold of the horse. The testing technique, dental dolorimetry, was easily performed. Tooth pulp pain thresholds (TPPT) were established on 8 nonmedicated adult male horses. Electrodes were nonreactive and remained functional for up to 98 days. Base-line TPPT values were consistent with repeated measurements on the same day and measurements on subsequent test days. The quantity of electrical current necessary to elicit the TPPT was increased after administration of xylazine HCl as a test analgesic. 相似文献
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Lin YL Moolenaar H van Weeren PR van de Lest CH 《American journal of veterinary research》2006,67(2):271-276
OBJECTIVE: To determine effects of microcurrent electrical tissue stimulation (METS) on equine tenocytes cultured from the superficial digital flexor tendon (SDFT). SAMPLE POPULATION: SDFTs were collected from 20 horses at slaughter. PROCEDURE: Tenocytes were isolated following outgrowth from explants and grown in 48-well plates. Four methods of delivering current to the tenocytes with a METS device were tested. Once the optimal method was selected, current consisting of 0 (negative control), 0.05, 0.1, 0.5, 1.0, or 1.5 mA was applied to cells (8 wells/current intensity) once daily for 8 minutes. Cells were treated for 1, 2, or 3 days. Cell proliferation, DNA content, protein content, and apoptosis rate were determined. RESULTS: Application of microcurrent of moderate intensity increased cell proliferation and DNA content, with greater increases with multiple versus single application. Application of microcurrent of moderate intensity once or twice increased protein content, but application 3 times decreased protein content. Application of current a single time did not significantly alter apoptosis rate; however, application twice or 3 times resulted in significant increases in apoptosis rate, and there were significant linear (second order) correlations between current intensity and apoptosis rate when current was applied twice or 3 times. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study indicate that microcurrent affects the behavior of equine tenocytes in culture, but that effects may be negative or positive depending on current intensity and number of applications. Therefore, results are far from conclusive with respect to the suitability of using METS to promote tendon healing in horses. 相似文献